Back to Winter Mode for my DIY ESS - Energy Storage System at Home making the best out of TOU rate

We are slowly entering winter here with pretty low temperatures in Paris, also the sun is lower and lower, allowing less and less solar production during the day, especially with grey clouds covering it sometimes all day long ....



So since last night, my DIY ESS goes back to its "Winter Mode", meaning it charges the battery pack at night, using half priced grid electricity - TOU plan -, and re-uses it through out the day



On the Power graph above, you can see that after the water heater has stopped at 00:30AM, the chargers continue to use 350W (limited to 4 chargers on purpose) until the electricity goes back to day rateat 6:24AM - and it started at 10:24PM the day before -

Follow my Live Power Usage and Generation with Solar and the DIY ESS



This is possible thanks to the Forced Charge Mode implemented in the Arduino program running my Home Energy Storage System




More on Forced Charge Mode on the DIY ESS Kit Website

DIY ESS Kit - General Presentation

After a year of successful Energy Storage at home, here is my very first Presentation of the system I designed from ground up ...



Here are the slide I made and commented for this video:















Visit my dedicated website here: http://www.diyesskit.com

DIY ESS - Energy Provider statement shows inverted low & high rate usage for October and December between 2012 & 2013

I have been charging (Forced Charge Mode on my ESS) at night for several months now since there is less Solar Production in winter. 

My last energy bill shows that, compared to last year october to december period, I inverted the usage in low rate and high rate

From Oct to Dec 2012 :  (no Solar and no ESS)

  ->   700 kWh used at night rate (half price)

  -> 1002 kWh used during the day 

From Oct to Dec 2013 : (Solar and ESS with Forced Charge Mode at Night 10:30 PM to 6:30 AM))

  -> 1021 kWh used at night rate (half price)

  ->   734 kWh used during the day

The funny thing is that the amount paid is more or less the same because price per kWh is rising, always ...


For more info on my DIY ESS, check out this other dedicated blog : http://www.diyesskit.com

DIY ESS - LiFePO4 CALB CA180FI Voltage Check

As I was moving my ESS upstairs one month ago,  and split the CALB CA180FI battery pack in pairs, I shot another small video doing a cell voltage check, and as usual, they are all in balance ...



The ESS battery pack is now charged and discharged fully in winter, using the low cost electricity provided by our energy provider TOU - Time Of Use - to charge, and discharging into our home grid during peak hours, mostly for heating, cooking and lighting

Winter: Charging during the night, using the Stored Energy from the ESSand Solar during the day

Winter: Charging during the night - off peak rate TOU -, and using the Stored Energy from the ESS and Solar during the day to shave peaks and compensate home usage as much as possible 

DIY ESS - First Full Night of Forced Charge Mode and the next day

After moving the ESS, now in the living room, we were ready to use the Forced Charge Mode all night long for the first time

Right after a good movie with the kids



Nikita: Always good to watch a good Luc Besson movie

At 10:30PM, when the low rate period starts, I just pushed the Control Board pushbutton for 4 seconds and the ESS went into Forced Charge Mode, switching all the Chargers on 

As you can see on the graph, after the water heater is done, only the ESS is on and using around 500W and was shut down at 6:30AM, end of the low rate period, using a regular AC timer, as the battery pack was almost full, its voltage showing 26.7V

Sunday morning, with a full pack the ESS helped a lot with the heating (Daikin heat pump),  breakfast, etc all along the morning and some lunch

This is the overview at the end of the day: We covered quite a bit of our Usage with the ESS and the Solar (sunny day for once)

And tonight, I will switch the ESS to Forced Charge Mode again ... in one hour exactly, before going to bed 

DIY ESS - Solar & Energy Storage under Grey Sky ...

We always see pictures and videos of Solar panels under a great sunshine, but to tell the truth, it is not always like this ...

Here are Energy Monitors, Graphs, Pictures and Video of the bare reality of what happens when the sun is hiding

Sometimes the solar generation is rather low - with my 1000W solar install - but still something is coming out of it steadily during the day; Now fall is here, sun starts producing around 9AM instead of 7AM, but around 200-250W all day long when the sky is grey

Fo rnow, no heating is required yet, and the ESS I built is doing the job: Capturing any excess/surplus of power into the Battery pack for later use and always keep the Net Usage (= Usage - Generation) as close to 0W as possible

Whenever a washing machine water heating cycle comes on, the ESS stops charging the Battery pack and uses the Energy saved in it to push it back into our home grid, reducing the usage from the utility company. It is really a Peak Shaving device  

As you can see, the ESS keeps the Net Usage around 0W; That's the yellow line on these graphs

Here we can see that the early morning consumption is not covered by the ESS anymore like it used to be during summer : The Battery pack voltage is too low and no Power will be drawn from it until it reaches a certain level with Solar; Also, at night, the sun setting earlier, I often see the SMA inverter quit around 6PM now especially when grey, and the ESS quicks in right away to supply all the household Power for lights, TV, computer, etc ... until the Battery is back to low and the ESS then quits too - If sunny the whole evening usage can usually be covered - 

When Power is required, the ESS switches from Charge Mode to Grid Tie Inverter Mode to help supply this additional Watts to our home

This video shows an example of power pushed by the ESS into our home while cooking lunch

As we go deeper into fall and heating will soon be on during the day, I think I will use the Forced Charge Mode on the ESS to start charging during off peak hours (TOU), at night, and start the day with a Fully charged Battery pack, ready to crush it !  :-)

Battery storage take 4: Skinny connections to yield fat savings

Last week at Clean Energy Week in Brisbane there were lots of energy storage products on display. Most of them were focused on the emerging “self use” market where householders attempt to maximise the use of their own solar generated energy in preference to buying power from the grid.

Reports from Europe indicate that “Self Use” is really taking off now that feed-in tariffs are being wound back in key solar markets like Germany. Our local solar market is also preparing for the shift in market behaviour and expected surge in the uptake of energy storage systems.

It now appears that these very same energy storage systems may also be the key to managing a new direction in electricity network charges, and it’s not Time of Use tariffs.

In a disappointing move earlier this year the Queensland Competition Authority increased the standing service fee for Queensland’s 12-month-old Time of Use Tariff 12 from $0.78 per day to $1.13 per day, a dramatic 44.8% rise. Anecdotally, few people have signed up for Tariff 12 in its first year and that’s unlikely to change given that the flat rate Tariff 11 continues to have a much lower $0.50 connection per day.

Given the enthusiasm for Time of Use (TOU) tariffs by the electricity utilities in the southern states, Tariff 12 has been seen by many in the Queensland solar industry as the end game for tackling residential peak load. Why then would the Queensland Competition Authority make this new, opt-in TOU tariff so unpopular? It seems that another solution may be waiting in the wings.

It has been highlighted a number of times that in Queensland, due to the flat rate connection fees charged to residential electricity customers, there is a heavy degree of cross-subsidisation by small peak load homes to support high peak load homes. Or in other words if your house doesn’t have an air-conditioner you’re effectively subsidising the connection costs of your neighbour that does.



With utilities like Queensland’s Energex and Ergon building out their networks to cope with peak load events that occur just a few hours per year, everyone pays so that some can enjoy heating and cooling during the coldest and hottest periods. Much political attention has been given to the alleged inequality of solar homes being subsidised by households without solar power systems. This begs the question “what’s being done about the inequality of connection fees for air-conditioning owners?”

Taking a look at how other markets are dealing with peak load can be instructive because the pressures on network costs being felt in Australia are hardly unique. A recent trial conducted by electricity network operator Alliander in the Netherlands limited household grid connections to just six amps – less even than a single lighting circuit from an average Australian home.

To ensure that the participants in the trial didn’t experience a dramatic reduction in their life styles, the utility provided each home with a 5kW PowerRouter solar power / energy storage system from Dutch manufacturer Nedap. This allows the local loads of each house to actually draw up to 25 amps as required without tripping the six amp connection.

PowerRouters are already available in Australia along with other products with similar Self Use capabilities such as the locally manufactured Selectronic SP Pro.

Restricting the size of the network connection into a house delivers a range of clear benefits to utilities in terms of network augmentation and complexity as well as to customers by driving increased energy efficiency. From the utility’s point of view they don’t have to estimate peak load, they just add up the connection sizes for each customer on each suburban transformer.

For consumers, especially small ones, being given the option to pay a network connection that’s just the right size is a great opportunity to save money and stop cross subsidising high electricity users.

Considering the Queensland government’s recent investigation into “Fair and Reasonable” Solar Feed-in Tariffs, it seems like offering customers the chance to pay only for the connection size they need will deliver great social benefits as well.

A further benefit is that inefficient and high draw devices like air-conditioners, electric storage hot water systems and pool pumps will be more closely scrutinised when customers can see the implications to their bills.

Under such a scheme Time of Use tariffs become effectively obsolete and utilities can continue to charge flat rate tariffs, which are far lower risk from a technology point of view.

Combined solar power and energy storage systems offer a clear path forward to make such skinny network connections a reality and deliver savings for both utilities and consumers. These systems produce solar power during the day with excess production “banked” for evening use. The integrated energy storage also acting as a buffer to ensure the network connection is never exceeded.

Advanced capabilities available with these energy management systems also include modern luxuries like customer web portals, household consumption monitoring and daily power production summaries. In the near future it’s expected that utility fleet management will also be rolled out to placate any fears the network operators might have.

Energy management systems featuring solar power and energy storage systems are the future for household electricity and now we just need skinny connections to unleash fat savings for frugal consumers and network operators alike.



Dane Muldoon is commercial sales director of Solar Guys, a Queensland company that installs solar panels and battery storage products.



Source: Renew Economy

Dick Smith wrong on Energy Costs - Renewables are Cheapest

"The only thing stopping an even faster rush for rooftop solar installs on domestic residences are discriminatory policies which prevent householders subject to a previous feed-in-tariff schemes from upgrading and adding more panels to their systems, and utilities that unreasonably limit the size of new systems"

Dick Smith has got the relative costs of fossil fuels, nuclear energy and renewable power all mixed up in his latest polemic, “Ten Bucks A Litre.”

I am from Energy security think-tank Zero Emissions and I wrote the Zero Carbon Australia Stationary Energy Plan which is briefly showcased during the film.

The stationary energy plan, the first of its kind to show that Australia could run on 100% renewable energy a combination of wind power, rooftop solar photovoltaic, and solar thermal with storage (featured in the film), along with a huge “mining” effort to find energy efficiency in housing, commerce and industry. It was a landmark that helped caused the Australian Energy Market Operator (AEMO), the organisation that runs Australia’s electricity supply, to write and publish this year its own plan and validate much of our work.

Whether you care about climate change or not, we’re moving rapidly away from coal because domestic and international banks, including the World Bank, will no longer invest in coal fired power. And a shift to gas would involve the burning of coal seam gas, due to a massive upswing in demand in Asia especially Japan the cost of gas here is becoming prohibitive.

The anticipated three-fold increase in the cost of gas (once we’re linked to international markets) means that wind power is now already the cheapest source of new energy capacity. And it is also cheaper for householders to generate their own power during the day from rooftop solar than to buy it through the meter from the big power companies. The only thing stopping an even faster rush for rooftop solar installs on domestic residences are discriminatory policies which prevent householders subject to a previous feed-in-tariff schemes from upgrading and adding more panels to their systems, and utilities that unreasonably limit the size of new systems.

The cost of gas being is being driven by the building of LNG export terminals in Queensland. Once we have a sizable link through these processing and port facilities to send gas including coal seam gas and shale out to the world’s markets, the gas market will mirror the oil market and always react to world pricing signals. We will never go back to having a sheltered market with gas as a cheap source of energy. What has really driven this international price up is the Nuclear disaster at Fukushima.


The Fukushima nuclear disaster two years back closed down a massive industrial manufacturing area for good, causing the abandonment of billions of dollars of factories and their robotic tooling and other plant. The cleanup bill is estimated at $60-70 billion and the country only has two out of 54 nuclear reactors operating. What’s more, it turns out that the two reactors that are operating were built atop a major earthquake fault line. So it is quite likely that they will be shut down in September, leaving Japan with no nuclear power plants at all.

Nuclear is the most expensive option when you take into account the external factors, followed by coal and coal seam gas. These external factors include devastating effects on health, agricultural output, land degradation, acid rain and the ability for us to feed ourselves, and of course in the case of the fossil fuels, climate change.

Already, in India and China renewables are either the cheapest form of new generation, wind is beating fossil fuels in Brazil and elsewhere. Even in Australia, wind and solar are considered the cheapest option for new capacity. Further price reductions are all about economies of scale, and economies of scale is what India and China have a lot of. Only renewable energy’s flagship technologies of wind power, rooftop solar and solar thermal with storage have small footprints and superior environmental performance, with innovation improving this all the time.

Dick Smith needs to revise his conclusion. If we want cheap power for the 21st century we need to invest much more in renewables, if we want to flounder, get sick and risk our economies then nuclear and fossil fuels will do the trick.

I look forward to a series of town hall debates with Dick Smith on the right way to a renewable future for Australia.


Source: Renew Economy

USA New Energy Storage Bill : Home owners can install their own ESS and get 30% off in tax credit !

US senators introduce energy storage bill

U.S. Senators have introduced a Storage Technology for Renewable and Green Energy Act for 2013. This Act, also known as the STORAGE Act, will promote the deployment of energy storage technologies in the U.S. All storage technologies are supported by the bill.

I read in this article that Home Owners could get a 30% tax credit building their own DIY ESS, which I think is great :-)

"Home owners can also install their own storage solutions. The Act will provide for 30% tax credit for homeowners for on-site energy storage to store off-peak electricity from solar panels for use when needed during peak hours."

Maybe some americans could be interested in my DIY ESS since they could pay only 70% of its cost ... which should be close to 3,000 USD after incentive (maybe less since many components can be found in the US). Pretty cool, things are starting to move...


My DIY ESS is doing exactly this, automatically: http://diyesskit.blogspot.com




Source: PV Magazine

Fighting Blackouts: Japan Residential PV and Energy Storage Market Flourishing

San Diego, CA -- In the past, a PV system with battery storage was associated with the off-grid system — not connected to the utility grid. The battery stores the energy produced by the PV system and when the sun goes down, electricity is drawn from the battery. In Japan, the battery became attractive to store electricity from "the grid," to reduce electricity bills.

After the devastation of the Tsunami and nuclear meltdown in Mach 2011, Japan became painfully aware of the importance of both safety and maintaining a steady supply of electricity. The combination of a PV system and battery storage gives consumers the ability to produce, store and supply electricity throughout the day at their own home for power outages and emergencies. However, the system can bring economic benefits — electricity bill reduction — during normal days.

Like California, utilities in Japan offer Time-of Use (TOU) rates. How homeowners can reduce electricity bills can be illustrated by using Tokyo Electric Power Company’s (TEPCO) current (non-summer) TOU rates for all-electric homes with a PV system.

- Purchase and store electricity from the grid at off-peak hour (11 pm – 7 am) at ¥11.82/kWh [US $0.12]

- Sell PV-generated electricity to the utility at the FIT premium rate of ¥38.0/kWh [US $0.38]

- Use PV-generated electricity during day time, otherwise paying at ¥30.77 (10 am – 5 pm) [US $0.31] and use stored electricity between 7 and 10 am and between 5 and 11 pm, otherwise paying ¥25.2/kWh [US $0.25]

With the battery storage, PV homeowners can ultimately buy electricity at the lowest rate (¥11.82/kWh or $0.12/kWh) and sell at the highest price (¥38/kWh or $0.38/kWh).

The key domestic PV makers, Panasonic, Kyocera and Sharp, all now offer lithium-ion battery storage along with a PV home system to meet consumers’ demand. Their goal is to move beyond PV and expand into a total Home Energy Management System (HEMS3) arena.

Kyocera started offering PV plus lithium-ion battery storage to homeowners in early 2012 with a target of selling 10,000 units from April 2012 to March 2013. Panasonic also released home battery storage systems that can be connected to Sanyo’s (now Panasonic) HIT PV system. The battery has a capacity of 4.65 kWh and is priced at ¥1.218 million MSRP [US $11,984].

In April, Kyocera released the largest residential lithium-ion battery in Japan. The battery has the capacity of 14.4 kWh, which is priced at an MSRP of ¥4.45million [US $43,784]. This large capacity allows it to power a home refrigerator, TV, computers, lights and cell phone chargers for up to 24 hours.

Kyocera has teamed up with Rakuten, Inc., which operates the nation’s largest internet shopping site, to offer a PV system (poly-Si) and a lithium battery (7.2 kWh) set for homeowners at an affordable price. Rakuten provides options with different sizes of PV systems with the battery, and installed system price (after tax) varies from ¥2.94 million ($29,730) with a-2.28 kW system to ¥4.168 million ($42,153) with a 6.27-kW system. These systems are installed by one of the nation’s largest installers, Nippon Ecosystem, which is part of Itochu Corp.

Residential battery systems remain expensive to average homeowners. To solve this issue,One Energy Corp. has just begun the nation’s first residential energy storage leasing service. Like SolarCity or SunRun’s PV leasing service in the U.S., this requires zero upfront payment to homeowners. The company is a joint venture between Orix, NEC and Epco. NEC provides lithium batteries, whose technology is used for Nissan Leaf electric vehicles.

Besides the energy storage leasing service, One Energy also offers “Yanekari (PV rooftop space leasing)” service. A homeowner can lease a storage system with 5.53 kWh of capacity at between ¥3,045 ($31) to ¥5,145 ($52) a month from One Energy while offering the roof-space to One Energy, making a monthly revenue of ¥2,500 ($25). The image below illustrates how a customer could use an energy storage system to offset the high cost of purchasing energy during peak times.




One Energy currently offers this leasing service in the TEPCO region only and is planning to expand to the Kansai region by the second half of this fiscal year and eventually expand nationwide.

NEC started mass production of residential storage systems in February. Besides partnering with One Energy, the company sells home batteries directly to homebuilders and building material distributors with the goal of selling 15,000 units during this fiscal year.

The company stated that PV homeowners will start storing PV electricity in batteries even more as the FIT rate gets lower in the future, creating a more self-sufficient and less grid-dependent environment.

It is declining, but the national government provides upfront, capacity-based rebates (¥15-20/kW) and a net FIT of ¥38/kWh on excess electricity generation for 10 years) for PV home systems. The government also currently provides a subsidy for lithium-ion battery storage for homeowners. The subsidy is one third of the installed system cost or up to ¥1 million ($10,823).

The hot and humid summer is approaching in Japan. Some of the nation’s utilities have just raised electricity rates and many of them will request that consumers limit and/or shift electricity consumption from peak to off-peak to control raising fossil fuel cost caused by the shutdown of nuclear power plants. With PV + battery systems, homeowners are moving to take energy matters into their own hands in defense against rolling blackouts and rising electricity bills.

Source: Renewable Energy World