by David Blitterdorf’s
I was recently invited to visit New Zealand, and am writing now amidst the summer temperatures of February in the southern hemisphere. During this trip to one of the only countries to legislate itself a nuclear-free zone, I’ve been absorbing info on New Zealand’s renewable energy economy, and considering the inherent wastefulness of burning fossil fuels to generate electricity.
We have a 200-year-old problem in the world of electricity production — the problem of large thermal losses experienced during the conversion of fossil, biomass or nuclear fuels into usable electrical energy. Almost all of the world’s electricity is produced through com-busting a resource. In power plants, these resources are consumed to heat water to make steam, which turns turbines to generate power. Nuclear fission reactors are simply large heaters to make steam. Likewise, almost all coal, oil, natural gas, wood chip and nuclear power plants boil water to move steam turbines, which rotate generators, thus producing electricity.
The problem is that the steam cycle is a huge energy waster. Sixty-seven percent — that’s most of — the fuel burned in a power plant is wasted in surplus heat generation, which is usually not captured for use in any other way. This adds up to a mind-bending statistic: Over 50% of the total energy consumed in the U.S. is used as part of the electricity-production process. It’s like we are taking two-thirds of our energy paycheck and setting it on fire. Cooling towers next to power plants evaporate vast amounts of fresh water to expel the waste heat of the steam cycle into the air. And in “hot dumping” this huge amount of energy, we allow it to be discharged into our ecosystems, requiring more resources to absorb and dissipate the thermal load. According to a November 2011 study by the Union of Concerned Scientists, almost half the fresh water in the USA is used to cool coal, nuclear and other fossil-fuel-burning power plants.
The top three energy sources that don’t use the steam cycle are wind and solar renewable energy, plus hydro-power. Instead of burning — and wasting — valuable resources to turn a generator’s turbine, falling water and blowing winds produce electricity by rotating a generator directly. Solar power requires no generator turbines at all; solar photovoltaic silicon cells convert sunlight to electricity on the spot. Solar, wind and hydro-power do not experience the same large thermal losses of traditional energy production methods. Modern wind turbines are up to 50% efficient in converting the blowing wind to electrical energy, with very little wasted heat. No heating our rivers, no need to use fresh water to carry thermal loads. These natural sources are all around us every day. Rivers tumble toward the sea, the wind blows and the sun shines. These real-time natural resources are truly renewable, because they are not depleted when used. We need to move quickly toward using only these renewable resources for our energy needs.
By contrast, fossil and nuclear fuels are one-time, finite fuels. These fuels were created over millions of years and are basically concentrated sunlight. It is tragic that these fuels are being burned so incredibly inefficiently when we can only use them once. Once burned, they are gone forever. It should be a crime to burn a non-renewable resource at such low efficiencies. At the end of the combustion process of the steam cycle, less than 35% of the original energy source is directly usable to us as electricity. The rest is gone forever – up in smoke, or steam. We need to drastically reduce our energy reliance on these sources, as quickly as possible. The earth cannot provide us with enough of them to keep up with our use, and at the rate we are going, we will soon deplete them all to the point of diminishing returns.
Here in New Zealand, most electricity is produced by water via hydro-power plants, but there are no nuclear power plants. New wind farms are being built to harness very strong winds. Solar also has a large untapped potential. Looking at this small island nation, I am impressed with what it has accomplished, despite – or perhaps because of – its relative isolation in an ocean at the bottom of the world. As I contemplate my upcoming flight home to the Green Mountain State, I wonder whether Vermont will similarly be able to lead, and become a model for how to do renewable energy right. I believe we must, and I have every hope we can.