Month: October 2006

Wood it be?

Posted on by roymacmullin

                                                       First published Telegraph Journal October 21, 2006

When looking at an energy problem, the most evident solution is not necessarily the best. For example, one of the problems that we have is the high cost of power plant construction. Typically, they have been costing close to $1 billion and that means an annual payment of $100 million. This will translate into a 10% rate increase for all of us including the industrial customers who object to high power rates these days. One would think that they would object to a new power plant if it could be avoided.

But we have built departmental empires that don’t communicate well or understand the whole picture. NB Power’s solution to a generation deficit is understandable and automatic – build a power plant. The PUB is there as a watchdog on NB Power and gets caught up in the game – what to build and when? The Energy department may have some ideas but what is their influence? And Efficiency NB – what is the story on their programs? How far does their mandate go?

New Brunswick has a power demand of 1600 MW in the summer and roughly 3200 MW in the winter. We have to build enough power plants for the highest figure. But what would happen if we could stop or even decrease our demand peak? This would mean that we wouldn’t require another power plant and wouldn’t require a $100 million rate increase. Or if we did decide to build a power plant, it would be to reduce greenhouse gases. (Wind turbines or hydro)

Lets assume that our annual growth is 1% per year or 32 megawatts. And perhaps we can assume that a power plant would be needed in the next 5 to 7 years to meet growth. Therefore, we would have to reduce the demand by 32,000 kW each year to defer this project. Assuming that 60% of homes are electrically heated, then that is roughly 132,000 homes in the provinces. 1600 MW / 132,000 provides an average heating contribution to peak is 12 kW. This is probably high as commercial and industrial space heating is included and perhaps a figure of 8 kW / per home is more likely.

The Liberal energy conservation program for homes at $60 million per year will affect roughly 30,000 homes. Of these 18,000 are electrically heated and will reduce peak demand by perhaps 1 kW for $2000 per home. If this program is effective, then we reduce growth down to 1/2 %.

Then, imagine a program to encourage people to convert from electric to another fuel, preferably wood. If the program cost was $2000 per customer, then we would only have to convince 1750 people for a total cost of $3.5 million to reduce growth to zero. (14,000 kW / 8 kW *$2000) The cost per kW of this program is $250 per kW versus $2000 for the conservation program. Both are valuable programs, but it can be seen that the off electric version is more cost effective.

One thing that tourists coming to New Brunswick note is the amount of forests here. Many people here heat with wood already and save money doing it. While there are many systems out there today, I want to talk about the pellet stove as it overcomes the basic problems with the standard wood stove.

Pellet wood stoves are growing in popularity for several reasons and particularly in the United States due to government support to reduce oil dependence. One of the major strength of these units is that they can provide an even heat for 24 hours or more by the use of its automatic feeding system. The pellets are made of waste wood, compressed into small pellets and packaged in 40-pound bags. According to George Jenkins, a researcher at the UNB Wood Science and Technology center, there is room for a large expansion of the pellet fuel market as there is considerable waste left in the woods. Perhaps 30% is left to rot on the forest floor, as some trees are crooked or partially rotten and have little commercial value. In addition, the emissions of these units are very good when compared to standard wood stoves, as the air intake is not restricted.

Burning wood is considered a carbon neutral activity as the rotting of wood is equivalent to the burning of wood from a CO2 point of view. However, when waste wood displaces carbon-based fuel such as natural gas or oil fuel, it actually reduces the CO2 load on the environment. As well, the expenditures on wood as a fuel stay within Canada and support our balance of payments.

Will we choose the standard answer for $100 million per year or the alternative at less than $10 million per year? Will the upcoming PUB hearings on load forecast be more of the same high-priced consultant feeding frenzy considering the minute mathematical details without understanding the greater options that are available to us? Will a real approach to demand control even be considered? Is the Liberal government ready to take control and organize the energy file? The previous government was considering a new coal plant. Will it be business as usual with politics trumping common sense? Only time will tell.

Reclaim waste heat from Power plants

Posted on by roymacmullin

Want to take a 1-minute course on power generation? Great! There is a little mathematics mixed in, but it’s not too difficult.

The key to understanding efficiency is realizing that the energy used from the fuel exceeds the electrical energy produced.

1 kWh (kilowatt-hour) is the basic unit of power measurement and is equal to 3412 BTU’s (British thermal units). One barrel of heavy oil, costing roughly $50 / barrel, contains 6.2 milllion btu’s. So that barrel should produce a tremendous amount of energy when burned and it does. But a considerable amount of the energy is released as heat and not usefully converted into electricity.

Heavy oil or coal is burned to create steam that turns turbines. Once through the turbine, water from the ocean cools down the steam to allow a pressure difference and more hot steam to flow. On it goes around the circle and power is produced.

It actually takes roughly 10,000 BTU’s to create 1 kWh (3412 BTU’s) which is 34% efficiency conversion. The remaining 6,588 BTU’s of energy are lost out of the steam and flows into the ocean.

So how did we end up with thermal power generation that produces 1 unit of electrical energy and throws out nearly 2 units of heat? The simple answer is that power plant design evolved from a time when oil was cheap, less than $10 per barrel. Secondly, huge demand for energy required more than hydropower was able to fulfill and windpower was not a cost-effective option back then. Thirdly, power companies were never mandated to look at the energy efficiency of the whole process or to cooperate with private industry or the community to use the waste heat.

Public Utility Boards are the utilities oversight committees but sometimes they don’t see the larger picture either. To make matters worse, utilities built plants in isolated areas to avoid public controversy, making it difficult to use the waste heat for homes, industry or agriculture. Such is the benefit of hindsight. What a terrible waste of energy!

There are instances in North America where CHP (combined heat and power) is used for process heat to increase the efficiency of the system to roughly 85%, similar to the level when we burn oil in an efficient home furnace.

Europeans are way ahead of us in this regard. The Beznau nuclear plant in Switzerland distributes roughly 75 Megawatts of waste heat to homes and businesses.

The economics of oil generation are not too good lately. One barrel of heavy oil = 6.2 Million BTU’s / 10,000 BTU’s per kWh = 620 kWh’s per barrel. $50 CAN per barrel / 620 = 8 cents per kWh just for the fuel. If we add another 3 cents for the annual capital cost of the plant and the operational cost, then oil isn’t looking very good at 11 cents per kWh and it’s just going to get worse price wise in coming years. And we haven’t even mentioned greenhouse gas emissions from an oil plant.

So the future of the Coleson Cove plant in New Brunswick, the Tuft Cove plant in Nova Scotia isn’t bright and Maritime Electric’s plant on the Island only runs when absolutely necessary anyway. So probably oil fired plants are not going to be running much in coming years. But how would we use some of the enormous waste from coal and nuclear plants that will be running for the long term?

  • Install massive agricultural greenhouses in the Lepreau or Belledune area in New Brunswick. Similar installations in Nova Scotia are possible. Commercial operators of greenhouses would see low cost heat as a real incentive to locate close to a power plant.
  • Invite industrial enterprises to use the excess process heat at reasonable cost.
  • Consider the possibility of an indoor water theme park with wave pools, and other attractions. The low cost heat provides the economic incentive. In the future, gas prices will kill long distance tourism and the only method to satisfy the human desire for a getaway vacation may be a unique local tourism destination.
  • Where economically possible, install district-heating loops to feed residential homes from existing power plants.
  • Use of the waste steam heat to economically separate hydrogen for use as a fuel.

To put this into perspective, the heat wasted from Belledune coal fired power station is the equivalent of 3.9 billion kWh’s. (400 Megawatts x 60% load factor x 8760 hours per year x 65/35% efficiency) This is 3.5 times the annual power usage of the residents of Saint John. If we price this at 5 cents / kWh, then we have $195 Million of heat wasted each year. The waste heat from Point Lepreau would be equivalent to 7.8 billion kWh ($390 Million) per year. Could a portion of this heat be saved and used for good purposes?

In the future, should we rethink some of the principles related to power plant siting and design so that waste heat becomes part of the energy solutions that we so desperately need? When Public Utility Boards evaluate proposals for new power plants, should they include planning for use of the waste heat as part of the process? Should greenhouse gas emissions be part of the economic evaluation? I certain hope so.