low-cost solar collector uses discarded wine bottles
This innovative low cost solar thermal collector uses salvaged wine bottles. It may be a primitive approach to tapping the power of the sun, but it is affordable, which is important in developing countries like China. A more advanced approach combines photovoltaic panels and electric cars.

Calculating a Zero Emission Lifestyle

What do you get when you combine EVs and PV? A Zero Emission Lifestyle.

By Christopher Morgan MD

The math of the Zero Emission Lifestyle can get complicated. For example, your zip code, the entry on line 17 of your form 1040 and the remaining lifetime of your house are all significant factors. Projecting into the future makes the job exponentially harder. Let’s see what we can do with some back of the envelope figuring.

Let’s talk about solar power and electric vehicles - a great combination for several reasons. Over the same distance, the amount of energy an electric car uses is less than 1/6 what a gasoline powered car uses what because electric motors are so much more efficient. Comparing an electric car that uses 250 watt hours per mile (gets 4 miles per kWh) to a car that gets 25 miles per gallon, if gasoline is $5 per gallon (20¢ per mile) you could power an electric car electrically if your energy cost was 80¢ per kWh.

Let’s start by looking at the additional cost of the electric car. Using the numbers given in this challenge, assuming a $10,000 premium for a battery car spread over its 100,000 mile useful lifetime, the implied extra cost for batteries and the power train is about 10¢ per mile, leaving 70¢ per mile for the electricity.

What does solar power cost today? It depends on how much you buy and what you end up paying for it. The smallest solar electricity system that most contractors will install is a 2 kW system, one which at mid-day in full sunlight will make 2,000 watts of power. A system like this would be big enough to power an electric car for 10,000 miles (less in Anchorage and more in Phoenix) and will probably cost around $18,000 installed. Cash rebates and tax credits may be available (see dsireusa.org for your state). In Oregon, we have excellent incentives and our final net price for 2 kW is about $5,500.

The value of the energy from a 2 kW system depends on a few things, like the amount you make and what you pay your electric utility per kWh. The amount you get depends on where you live, how the panels are oriented and if any shadows fall on them. A well situated 2 kW shadow-free system in Portland, OR makes about 2200 kWh per year, similar to an average US city (go to pvwatts.org to calculate the output of a 2 kW system in your home town). Around the country, the cost of electricity averages 10¢ per kWh but ranges from 7¢ to 24¢ cents. People living in the same city can pay significantly different rates depending on which utility serves them. Your bill will show you what rate you pay.

If your net cost for a 2kW system were $18000 and if you financed it with a 25 year loan at 6%, your payments will total a little under $1400 per year. Half of the cost of a 25 year loan is for interest, some of which might be deductible. Under the worst circumstances in the US, solar electricity could cost 60¢ per kWh, well below the 70¢ needed to make a solar powered EV cost the same as a gasoline powered car.

Solar Power: The New Security

Why bother with solar power for your car, even if it is Green, if it seems to cost more than regular electricity? One big reason is that your solar power loan payments stay the same but the value of your power keeps going up. Electricity costs now are 160% of what they were ten years ago. At this rate your system will be making over $600 of electricity each year at the end of a 25 year loan and will probably keep going well beyond that. Even if electricity from solar panels costs you more at first, it won’t take long for the cost of electricity from your utility to catch up with and exceed what you are paying.

Another big advantage of solar power is that you do not pay tax on what your system makes. For example, if you are in a combined 24% state/federal tax bracket (the lowest in OR) the $220 income from a year of solar power is equivalent to an extra $290 in your pay check. The after tax value of solar power rises to $380 for taxpayers in the highest tax bracket. This is similar to the return from an investment in a long term bond fund.

Even for taxpayers in lower tax brackets the long term return on an investment in solar panels could beat the return of bonds, because of the high inflation rates of utilities in the US. This is especially true if the system lasts 40 years, which is quite possible. It would give you 15 years of “free” income and tip the scales heavily toward solar power.

It’s About to Get Even Better

In the near future, solar panel prices will decline significantly because several new high purity silicon producers will come to market, ending a shortage that has kept prices high, and because production of lower cost products using thin films and other new technologies is ramping up.

That electric car may not be far off, either. There will probably be several battery powered cars from major manufacturers to choose from in a couple of years. Even if you paid full retail price for your solar panels at today’s prices, with this electric car your driving would cost the same as a current gasoline sedan and would be a heck of a lot more fun to drive.

Priceless Intangibles

I have a few final comments as a solar power owner. Recent generations have grown up in prosperity with plentiful energy. We are used to plunking down significant sums of money up front for shelter and the ability to travel 40 miles with ease. We do not have home power equipment because utilities have been cheap and the equipment has been too expensive. Everyone balks at the idea of putting down a chunk of change for home solar power. Surging utility prices should make everyone examine this hang-up because the economics of solar power are superb over the long term when rising energy costs are rising like they have been. Solar power is now affordable and financially smart in many parts of this country.

Solar power owners love their systems. We see them every day and know they have made energy. They are a signpost on everyone’s road to independence and energy freedom. They make our lives brighter because the sun helps fade our worries about the future.

We need to have both renewable energy and fuels for a flexible, durable supply of energy. We all realize now that our supplies of fuel are finite and we will need fuel for a long time. As a scientist, I notice that over their lifetime solar panels give back about 10 times the amount of energy used to make them (1000% efficiency), and the fact that electric cars are so efficient (500% better than gasoline cars). I feel a strong imperative to take advantage of this by putting them together – and the sooner the better.

As a father, I feel that if I can afford something and it saves fuel effectively, I need to do it so my children will have the energy they need when they are my age. For me, this is the bottom line.

Now is the time to start learning about solar power and saving for your panels. Consider solar hot water, too. This equipment costs half as much ($8500) and uses half the roof space of solar cells (70ft2), the price of natural gas is rising much faster than even the price of electricity, and the system likely to be an unbeatable investment. Consider wind power for your car if you live in a windy area. Both wind and solar power save fossil fuel. Ask me any questions you would like. I would love to hear from and am glad to help in any way I can.

Times Article Viewed: 11930
Published: 28-May-2008


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