No Carbon with my Chunky Fries Please!

No Carbon with my Chunky Fries Please!

By: Jerry Yudelson - Tuesday, May 27, 2008
Source: iGreenBuild.com

Returning from the U.K. after another week of glorious weather (Global warming will make Merry Olde England quite more habitable, of course), I’d like to think I’ve seen the future of the debate in the U.S. over a low-carbon or zero-carbon future, and it’s as confusing as one could ever imagine.

For example, by 2016 all new homes in the UK are supposed to be built to zero carbon standards (called Code Six), with at least 20 percent of the zero carbon balance coming from onsite renewable sources, almost an impossibility in cloudy, northerly England, Scotland, Wales and Northern Ireland. The first Code Five apartments were built, in Surrey with a horrific cost premium of 24 percent, about $80,000 per unit. Even the builder figures that the cost premium will be no less than 20 percent. The homes include about 8.5 PV modules each for a cost of $17,000 per home (I just put 9 modules on my home at a gross cost of about $12,000) and a wood-pellet biomass boiler costing about $11,000 per unit. (Source: Building magazine supplement, “The Rules of Engagement,” April 2008.)

Interestingly, the UK government includes biomass boilers in the definition of renewable energy sources, but neglects to include the transport costs of the wood pellet supply. Studies that I have seen also show that the total biomass production in the entire country would fall far short of supplying all the homes with wood pellets. I think pellet boilers are OK for some of the colder and forested regions of the US, especially those currently relying on fuel oil, but are not a practical solution for most of the country, especially in areas where the standard home heating fuel natural gas.

Now British attention is turning to developing a similar “zero carbon” requirement for new commercial buildings by 2019. One of the key issues is that non-residential buildings are far more diverse than homes, ranging from short and tall offices, to shopping centers and malls, restaurants, hotels, churches, recreation centers, data centers, factories, schools, laboratories, hospitals and stand-alone stores such as a Wal-mart or Best Buy. You can imagine the difficulty in writing a zero carbon set of rules for such a diverse range of building types, sizes and end-uses, in each of the eight major climatic regions of the U.S. In the U.K given the three to five year cycle for planning, budgeting, permitting, building and occupying major structures, this 2019 regulatory date means effectively that all issues have to be resolved by 2015 at the latest, less than seven years from now. That’s a tall order for change in a $250 billion industry.

Nonetheless, the low carbon future is something that will hit the US quite soon, with both Presidential candidates talking about global warming and the prospect of a heavily Democratic Congress in 2009 and for some years to come. Well, what exactly does zero carbon really mean? Here are some possible definitions, each a bit more confining. (Imagine a President saying, “I did not have carbon with that woman,” and then trying to define it more precisely.)

First, what energy demands are we going to address with zero carbon? Most of the thinking to date has been about heating, hot water, lights and cooling. But in many homes and commercial buildings, other uses of electricity account for a quarter to more than half the total energy demand, so we can’t realistically exclude them. But in commercial buildings, the so-called “process loads” vary considerably from one type to another.

Should homes and buildings each have zero net carbon requirements or can some places that generate more renewable energy than they consume help offset those that don’t? For example, can I pay my neighbor to put more PV on his roof if mine is shaded? (We do have to acknowledge the positive benefits of trees and shade in urban environments even if they on occasion may hinder renewable energy production.)

Does the net carbon requirement apply to “source energy” or only “site energy”? If my use is 15 kWh per year per square foot, do I have to offset the 50 kWh (170,000 BTU) of fossil energy it took to produce it? If it’s source energy and the efficiency of the overall grid is about 30 percent, then I’ll have to offset more than three times my actual energy use to have a clean slate. The inclusion of source energy also makes a powerful argument for onsite energy production using cogeneration or microturbines, to use the thermal energy from fossil sources that’s wasted at the power plant.

Now consider energy supply: does a zero carbon energy source have to be onsite, nearby (e.g., connected by a wire to the end use) or can it be off-site completely (such as energy from large PV and solar thermal electric arrays)? Can we have a total annual net zero carbon, for example, with fair weather solar, while acknowledging that we’ll have a requirement for “dirty carbon” sources in foul weather? Drawing the boundary is difficult, as one can see now in the debate over carbon offsets. Does the replacement renewable energy source even have to be on the same continent, if it’s cheaper for me to buy it there? After all, global warming is a global problem that argues for both local and global solutions.

Should we count biomass power because it takes lots of fossil fuel to produce the biomass feedstock (other than from forest culling, in which case, there’s still the transportation cost), even neglecting the concern that of our biomass from farm and field should be feeding people instead of providing energy?

Could some of the total cost of achieving zero carbon buildings, one by one, be more effectively deployed in large-scale renewable energy generation or other carbon mitigation strategies, such as recovering carbon dioxide generated by coal-fired power plants? After all, any economy has only so much money to invest in building energy conservation and renewable energy supply, without pinching other needs such as paying for the Boomers’ looming retirements.

One thing is sure: these questions offer great opportunity not only for consultants but also for new technologies. Here’s a good one: why not use the open parking lots around buildings to generate solar hot water for nearby buildings, by putting a lot of water pipes right under the asphalt and then extracting the heat to provide hot water for buildings? Now you have a solar collector that will work even if we just use the aisles in a parking lot! (Some Dutch folks published this idea last year, so don’t rush to the patent office!)

This is getting quite complicated. Perhaps that’s why Brits spend so much time in their pubs hashing out these issues. For me, I think I’ll order some mayonnaise for those chunky fries!