The Blog - The Good Life

If I was honest, when I first became sufficiently interested in renewable energy to spend money learning about it, I sub-consciously saw myself as a high-tech version of Tom Good (A 1970's TV series starring organic vegetables, self sufficiency, a goat and Feclicty Kendal).  After an 18 month period messing with a small solar panel in the back garden, some hard lessons were learnt.

The first lesson was there had be some balance between supply and demand.  Back in 2006, our household of 2 old adults and 3 young ones was consuming between 5,000 and 7,000 kwh/year.  At the time, the cost of a 2.5 Kw roof mounted PV system with a likely yield of 2,000kwh was around £10,0000.  The first step was to look at consumption.  With not much effort and little expenditure, this came down to around 2,500 kwh/year.  A large proportion of that came from replacing incandescent light bulbs with CFLs, replacing a particulary nasty fridge and swapping old desktop computers for laptops, something which we were going to do anyway.  I have only anecdotal evidence for this statement, but it seems that when family installs solar panels on their roof, there consumption falls to something close to the electricity generated.  This leads to the question, how can you bring around a fall in consumption without first putting a lot of money on the roof?

Once the fridge had been responsibly disposed of, the economics became clearer.  The electricity bill was around £350/year.  My view is that the best way to increase the adoption of environmentally friendly technologies is for them to make some economic sense.  Having even less money than Tom Good, I could not afford an investment with a 30 year payback.  I could get a better environmental and economic return by sorting out the mess that was the domestic hot water system.  Feed-in tariffs and rising energy costs have changed the economics, but I don't want to go there.

At this point, my interest in renewable energy became, literally, academic and like a true academic I have  not come to a conclusion.  I wanted to know about the availability and cost of renewables and consider what might happen if you thought about energy without the safety net of a connection to a fossil/nuclear power station.  Over a period of one and a half centuries, western energy economies have evolved to supply as much energy as anyone wants to pay for.  The fossil/nuclear grids have been successful in supplying cheap and reliable energy.  Until early in the 21st century, energy costs as a percentage of household income were falling (note to self, check this statement).  Electricity consumption has not been constained by availability and this makes it hard to move to a sustainable energy economy based on renewables who's output is a function of the weather.  The fossil/nuclear grid is a valuable part of our economy, not even the most ardent environmentalist wants a railway system which relies on the wind (remember the wrong kind of snow?).  In contrast, emerging economies in Africa which do not have an existing grid system are demonstrating what can be achieved with small solar panels and the careful selection of tecnologies, mobile phones, computers and LED lighting don't use much energy, yet can be life changing.

I'm always suspicious of research which appears to be a statement of the obvious, thus I describe my efforts with the small solar panel in the back garden as a statement of the problem.  The Solar Bucket as it became known was simply a 5W solar panel connected to a 4.2 AH lead acid battery, during the day, the panel charged the battery, overnight the battery powered something (a fan, resistors or an LED light).  The stabilised voltages at dawn and dusk were used as a measure of the energy captured.  The first lesson was that my neighbours are more tolerant than my family.  There was a large difference in yield between a clear sunny, summer day and an overcast winter one.  This in contrast to demand which is at its peak durin winter evenings.  Therefore, a system has to be designed for winter conditions by maximising the yield and minimizing the deman.    Except on clear sunny days and overcast ones, the output of the panel fluctates with the passage of clouds.  Clouds can reduce the annual yield of a system to 60 - 70% of the theoretical yield under a clear sky.  The solution to uneven supply is storage and the bigger the better.  I'm forming the view that storage is the critical element in a renewable energy system.  The Sun does not shine at night and the wind only blows when your wife/partner wears a hat.  Until recently, storage has not been a big part of electrical distribution, the underlying concept being  that power stations adjust there output to the current demand.  However, the growing interest in hybrid and electric cars has resulted in the cost of batteries with capacties between 10 kwh and 50 kwh falling.  If a household can get it's consumption down to 5 kwh/day (not easy, but not impossible), then with 10 days of buffer storage, energy self sufficiency gets a step closer.  The real challenge is December and January.