Joey Hess has designed, built and tested an off-grid, solar powered fridge, with no battery bank. Using an inexpensive chest freezer with a few modifications, the fridge retains cold overnight and through rainy periods. The set-up consists of a standard chest freezer, an added thermal mass, an inverter, and computer control. He writes:

The battery bank is a large part of the cost of a typical off-grid fridge installation. It needs to be sized to run the fridge overnight, as well as for several days of poor weather. Cheaper batteries only last 3-5 years, and longer lasting batteries are correspondingly expensive; either way a battery bank for an off-grid fridge is extremely expensive over the lifetime of the fridge. By storing solar power in the form of cold, I can avoid the battery bank expense and environmental footprint. The only battery power it needs is enough to turn it off cleanly when the solar panels stop producing — a few minutes of power instead of days — and a small amount for its computer control.

Joey’s off-grid, solar powered, zero-battery-use fridge has successfully made it through spring, summer, fall, and winter:

I’ve proven that it works. I’ve not gotten food poisoning, though I did lose half a gallon of milk on one super rainy week. I have piles of data, and a whole wiki documenting how I built it. I’ve developed 3 thousand lines of control software. It purrs along without any assistance.

Read more:

• Fridge 0.1
• Fridge 0.2
• Fridge data
• Fridge Wiki

Related:

• “Daylight Drive” DC Solar Power at the Living Energy Farm

Thanks to Roel Roscam Abbing.

Reader Goran Christiansson sends us a link to Living Energy Farm, a research and community project in Virginia, USA. Most notable is their use of “Daylight Drive” DC solar power without batteries for workshop tools — reminiscent of the ideas outlined in How to run the economy on the weather. Also of note is their choice for less efficient but more durable Nickel Iron batteries for lighting.

Below is an excerpt from the introduction page:

“The vision of Living Energy Farm (LEF) is envisioned to be a community that is food and energy self-sufficient. We are off-grid, and we are putting together the means to run our farm without fossil fuel. Our intent is for Living Energy Farm to operate on a modest, globally applicable, renewable energy budget. We have found that this global perspective differentiates us from most other projects working on sustainable technologies.”

All of LEF’s DC shop tools and most of our appliances run “daylight drive” straight from the solar electric (PV) panels. We run high-voltage industrial DC motors with no batteries, no inverters, no costly or fragile electronics whatsoever. This is a MUCH cheaper, simpler, and more durable way of utilizing solar energy.

“In starting Living Energy Farm, our plan was to pull together renewable energy technologies already in existence rather than “re-inventing the wheel.” We have found that we cannot buy a lot of what we need, and thus we are having to build some of the tools and machines we need. We live, day by day, off-grid and (mostly) without fossil fuel. We experience the benefits and limitations of our own ideas every day.”

“We have assembled a set of documents to explain how our unique, off-grid systems operate. We suggest you review “Longterm Integrated Village Energy (LIVE) — community energy systems that make centralized power grids unnecessary” before proceeding to the other documents. That will give you an overview of the design process at LEF.”

At Living Energy Farm, our conservationist design means we need very little stored electricity. We store electricity with nickel iron (NiFe) batteries, a very old, very durable battery technology. Nickel iron batteries tolerate tremedous swings of voltage input and discharge rates that would destroy any other kind of battery.

“We have been pleasantly surprised by how well our DC Microgrid has worked. We have found a much, much better way to live off-grid. The widespread adoption of the tools developed at LEF could widen access to energy services for people all over the world while radically decreasing our environmental footprint. We are trying to spread these tools far and wide, and looking for support in that work.”

Living Energy Farm. Overview of all technologies (pdf).

GIWHs are currently the least expensive form of energy storage available. Utilities can use fleets of grid-enabled water heaters for load shifting, demand response, arbitrage, ancillary services, or to respond to unexpected grid-stabilization events. Traditional dissemination of new water heater technology has been a painstakingly slow process, but water heater rental programs may greatly accelerate this process.

Read more: Battery Killers: How Water Heaters Have Evolved into Grid-Scale Energy-Storage Devices, David Podorson.

Related: How sustainable is stored sunlight?

The energetic implications of curtailing versus storing solar- and wind-generated electricity, Charles J. Barnhart et al, Energy & Environmental Science, Issue 10, 2013. Open access. Via Eurekalert and Yale Environment 360.

“We develop and provide a transparent life cycle inventory of conventional and electric vehicles and apply our inventory to assess conventional and EVs over a range of impact categories. For all scenarios analyzed, the use phase is responsible for the majority of the global warming potential (GWP) impact, either directly through fuel combustion or indirectly during electricity production.”

Total emissions

“When powered by average European electricity, EVs are found to reduce GWP by 20% to 24% compared to gasoline ICEVs and by 10% to 14% relative to diesel internal combustion engine vehicles (ICEVs) under the base case assumption of a 150,000 km vehicle lifetime. When powered by electricity from natural gas, we estimate EVs offer a reduction in GHG emissions of 12% compared to gasoline ICEVs, and break even with diesel ICEVs. EVs powered by coal electricity are expected to cause an increase in GWP of 17% to 27% compared with diesel and gasoline ICEVs. Wind power electricity would allow electric transportation with life cycle carbon footprints as low as 106 g CO₂-eq/km.”

Vehicle production: Manufacturing one electric car takes as much energy as manufacturing two conventional automobiles

“Comparative Environmental Life Cycle Assessment of Conventional and Electric Vehicles“, Troy R. Hawkins, Bhawna Singh, Guillaume Majeau-Bettez, Anders Hammer Strømman, in “Journal of Industrial Ecology”, October 2012. Via the BBC and Treehugger. Picture: Trexa. Previously: The status quo of electric cars: better batteries, same range.